IRS backlog - handling disputes

[TexTaxToo]

A CP14 notice was received in December 2020 assessing a penalty for failure to pay sufficient estimated tax for 2019.  Most income was received in December 2019, and estimated tax was paid before Jan. 15, 2020.  The return included Form 2210 with the annualized income installment method, which shows no underpayment.

In early January, a letter was sent to the IRS explaining this with a copy of Form 2210.  Subsequently, CP501 and CP503 notices were received, and a followup letter was sent.  There has been no response to either letter, which isn't surprising considering the backlog.  Now a CP504 notice was received.  What would you do?

[Gail in Virginia]

I would probably get a signed 2848 if I didn't already have that, get all the paperwork together to be able to fax it, and call the practitioner priority line and ask for their help.  I don't know if that would work, but that is what I would do.  Writing letters at this point doesn't seem to be working. 

[TAXMAN]

For someone who is not an EA will the 8821 work if they were the preparer?

Got 2 2016's denied but we know were filed on time and refunds denied.

[ampCT]

I know this probably won't help preparers, but I've been lurking around Reddit's r/tax. It sounds like some taxpayers whose checks were cashed and are getting notices have gotten help calling the Taxpayer Advocate's office. Maybe call TA with the client in the office?